华北克拉通赞皇地区新太古代地质事件及对古俯冲带热构造过程的启示

古老俯冲带变形变质历史和热构造演化研究可为地球早期演化和板块构造启动时间及机制提供关键参考。华北克拉通约2.5Ga和1.8Ga构造-岩浆-变质事件在其形成演化过程中至关重要。赞皇地块内保留有一套新太古代晚期蛇绿混杂岩，并伴生同期深成花岗岩体和高级变质岩，为研究太古宙俯冲带热构造演化及早期地球动力学体制提供了构造-岩浆-变质作用的综合有利条件。本项目拟对赞皇蛇绿混杂岩及伴生的同期深成花岗岩和变质岩，开展野外大比例尺精细填图、构造解析、全岩和矿物地球化学、变质地质学和地质年代学等多学科研究，厘清混杂岩和深成岩体的构造成因关系，限定岩体岩浆成因来源，解析变质-变形关系，确定变质年代并构建P-T-t-D轨迹，约束赞皇蛇绿混杂岩形成及变形变质演化史，进而探讨其热构造演化动力学过程。本项目可望为深入研究华北克拉通基底形成演化和太古宙古俯冲带热构造演化过程提供重要地质依据。

The study of thermal condition, deformation and metamorphic history of paleo-subduction zones can provide key information for early earth evolution, operating time and regimes of plate tectonics. Both the circa 2.5 Ga and 1.8 Ga structural-magmatic-metamorphic events play important roles on the tectonic evolution of the North China Craton. Previous studies show that a late Neoarchean (circa 2.5 Ga) ophiolitic mélange is well preserved in the Zanhuang Complex in the Central Orogenic Belt of the North China Craton. This mélange is accompanied by coeval granitic plutons and high-grade metamorphic rocks, which provides an excellent opportunity for deciphering the structural, magmatic and metamorphic history of Archean subduction zones and geodynamics in the early earth. Based on multi-disciplinary studies of large-scale field mapping, structural analyses, whole-rock and mineral geochemistry, metamorphic geology and geochronology of the Zanhuang ophiolitic mélange, coeval granitic plutons and metamorphic rocks, this project aims to clarify the structural and genetic relationship between the Zanhuang mélange and granitic plutons, reveal the magmatic source of granite, confirm the structural-metamorphic relationship and metamorphic age, and reconstruct the P-T-t-D path, then discuss the thermo-structural processes. Finally, this project will further constrain the formation, deformation and metamorphic history of the Neoarchean Zanhuang mélange, and provide key geological evidences for the early Precambrian tectonic evolution of the North China Craton, as well as the thermo-structural evolution of the Archean paleo-subduction zones.